Data Warehousing is the procedure of designing, and maintaining a Data Warehouse system.
Data Warehousing is a method for gathering and controlling data from different sources making the data easily available for querying and analysis.
A Data Warehouse is a compilation of information/data prearranged so that it can effortlessly used for querying and data analysis.
Data warehousing is not intended for up to date data usage.
Data warehouses usually contain huge amounts of data, divided in logical units called dependent data marts.
Data Warehousing has 2 main functions. The first function is to integrate the information/data coming from different data sources. The second function is to separate the data in the live data sources from the data in the actual data warehouse, which is used for reporting and data analysis.